<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    section{
      display: flex;
    }
  </style>
</head>
<body>
  <section>
    <div>1</div>
    <div>2</div>
    <div>3</div>
  </section>
  
  <span>1</span>
  <span>2</span>
  <span>3</span>
  <button>1</button>
  <button>2</button>
  <button>3</button>
</body>
</html>